KR19980064275A - Bearings and bearing devices with hydrostatic porous oil - Google Patents

Abstract

Two bearing bodies 1 having bearing surfaces 17 are press-fitted into the housing 7 with one end open and the other end closed, and an axis 2 (rotating shaft) is inserted into the bearing body 1 to be spaced in the axial direction. Two porous oil bearings (A). The inner peripheral surfaces of the bearing body 1 and the oil leakage preventing member 11 are formed with a plurality of inclined grooves (dynamic pressure generating grooves 5 and air flow generating grooves 12). A solid lubricating composition 3 composed of a synthetic resin as the base material and an oil as a lubricating component by mixing lubricating oil or lubricating grease is disposed between two bearing bodies 1.

Description

Bearings and bearing devices with hydrostatic porous oil

The present invention relates to a dynamic pressure-containing porous oil-containing bearing and a bearing device in which the porous body contains lubricating oil or lubricating grease so as to have a self-lubricating function while fluidly supporting the sliding surface of the shaft by the dynamic pressure oil film generated in the bearing gap. , Bearings and devices are particularly suitable for use in polygon mirrors for laser printers, spindle motors for magnetic disk devices which are required to rotate at high speed with a high degree of accuracy, and the like.

Porous oil-containing bearings are variously used as bearings having self-lubricating properties. However, since it is actually a kind of circular bearing, when the axial eccentricity is small, it generates unstable vibration, causing a so-called vortex in which the shaft rotates at a rate of half the rotational speed. As regards the measurement for this, the formation of dynamic pressure generating grooves such as herringbone or threaded in the bearing surface can be mentioned as an example. Conventionally, dynamic pressure generating grooves exist in porous oil-bearing bearings to support the shaft while suppressing unstable vibration by utilizing the dynamic pressure generated by it, examples of such a configuration include Japanese JP 64-11844 and Japanese JP 63. -19627.

Japanese Unexamined Patent Application Publication No. 64-11844 discloses a bearing device in which a porous oil-containing member having a herringbone groove on a rotating shaft is fitted and combined with a sleeve having a cylindrical radially inner peripheral surface. On the other hand, Japanese Unexamined Patent Application Publication No. 63-19627 discloses the formation of shiny dynamic pressure generating grooves on the bearing surface of a porous oil-containing bearing.

According to Japanese Patent Application No. 64-11844, a porous oil-containing member having a herringbone groove is fitted to the rotating shaft with the intention of utilizing centrifugal force accompanying the rotation of the shaft, causing the outflow of oil into the bearing gap. This configuration has the following problems.

(1) The number of parts of the bearing device usually increases from two (rotating shaft and bearing) to three (rotating shaft, porous oil-containing member, and sleeve (bearing)), which complicates the assembly operation and increases the cost.

(2) In the case of a hydrodynamic bearing device requiring a high degree of dimensional accuracy, there are about three parts in which each accuracy affects the accuracy of the subsequent assembly, which is more intended than in the case of a two-piece bearing device. Obtaining accuracy becomes more difficult.

(3) During rotation, centrifugal force continuously acts on the porous oil-containing member. Therefore, the oil is continually leaked out, causing the oil to seep into the bearing gap sooner or later with a continuous rotation that causes the oil to leak into the bearing gap. This means an inevitable flow of oil.

According to Japanese Patent Application No. 63-19627, the bearing surface of the porous bearing is formed with a polished dynamic pressure generating groove. Such a configuration has the following problems.

(1) Since the groove has a sealed opening, the circulation of oil, which is the biggest feature of the porous oil-containing bearing, is hindered. Therefore, the oil spilled into the bearing gap is compressed to the bend of the groove by the action of the herringbone groove, and stays there. A large shear action is present in the bearing gaps that exerts this shear force and frictional heat on the oil staying in the oil grooves, resulting in denaturation, and an increase in temperature causes premature oxidative denaturation of the oil. Therefore, bearing life is shortened. On the other hand, in conventional porous oil-bearing bearings, the retaining oil circulates with the rotation of the shaft through the bearing clearance and inside the bearing, so that no shear force is applied continuously, and even once heated, the oil is forced to rise due to temperature rise. There is little risk of oil being oxidatively denatured.

(2) It is very difficult to perform the sealing treatment to the grooves. The specification of the related publication suggests that the sealing can be carried out by a molding operation. However, the depth of dynamic pressure grooves is generally on the order of μm and such compression molding is not effective for sealing the openings at the surface. In addition, the specification of the publication mentions coating as another means of forming operation, in which the thickness of the coating film should be smaller than the depth of the groove, which means that it is very difficult to apply the coating film which is several micrometers thick only for the inclined area. .

The object of the present invention is

(1) reduce the number of bearing parts to two, save cost, increase the accuracy of parts more easily, apply to mass production,

(2) the holding oil is circulated through the bearing gap and the inside of the bearing to provide a configuration that prevents the degeneration of the oil,

(3) Finding bearing specificity that allows dynamic effect to be exerted regardless of the presence of opening in dynamic pressure generating groove to make bearing design that can be industrially executed.

1 is an axial cross-sectional view showing an embodiment of the present invention.

2 is an axial cross-sectional view showing the movement of oil in a porous oil-containing bearing in which a herringbone type dynamic pressure groove is installed.

3 is an axial cross-sectional view of a porous oil-containing bearing for evaluation test.

4 is an axial cross-sectional view of a porous oil-containing bearing for evaluation test.

5 is a graph of evaluation test results

6 is an axial cross-sectional view of a porous oil-containing bearing for evaluation test.

7 is a radial cross-sectional view of a porous oil containing bearing.

8 is a graph showing evaluation test results for finding a relationship between c / h and axial vibration.

9 is a graph showing the amount of time-dependent change in oil separation ratio of a solid lubricating composition according to the present invention.

10 is a graph of comparative test results with and without a solid lubricating composition.

11 is an axial sectional view showing movement of oil in a porous oil-containing bearing provided with an oil leakage preventing member.

12 is an axial cross-sectional view of a typical porous oil containing bearing.

-Explanation of symbols for the main parts of the drawings-

1: bearing body 2: rotating shaft

4: bearing gap 5: dynamic pressure generating groove

6: ridge 7: housing

8: rotor 9: thrust support

When dynamic pressure generating grooves (herringbone or helical inclined grooves) are formed in the bearing surface of the bearing body 1, as shown in the axial cross section, the flow of oil is as shown in FIG. 2, for example. As indicated by the arrows, oil flows from the opening in the bearing face 17 (inner face) of the bearing body 1 to the bearing clearance 4 between the bearing face 17 and the rotating shaft 2, thereby providing proper oil circulation. It is preferable that the opening is distributed almost uniformly in the ridge line 6 between the dynamic pressure generating groove 5 and the groove (see Fig. 7). When the opening ratio at the surface is reduced, the movement of oil is difficult, on the contrary, when it is increased, the movement of oil is less difficult. In addition, since the viscosity of the oil retained must match the oil movement, the lower the viscosity, the easier the oil is to move, and the higher the viscosity, the more difficult the oil to move. In addition, in this specification, the term opening means a portion of a hole which forms the porous structure of the bearing body of the porous material which opens to the surface.

The combination of high opening ratio and low viscosity allows for extremely smooth movement of the oil, but high oil is easily pushed into the bearing body due to the action of the dynamic pressure generating groove 5, so that the oil is easily pushed into the interior of the bearing body. Not only can the rotation of the accuracy be maintained, but the dynamic pressure effect is reduced such that the contact between the shaft 2 and the bearing body 1 causes the wear of the bearing body 1, thereby deteriorating the bearing function. On the contrary, the combination of low opening ratio and high viscosity makes it very difficult for oil to move, so that even when the generated dynamic pressure is high, proper oil circulation deteriorates, and torque is increased, so that the drop of oil does not increase the bearing temperature. Promoted by

Therefore, the opening ratio and the oil viscosity have an optimal range to enable the generation of a dynamic oil film necessary for fluidly supporting the shaft and the proper circulation of the oil.

To clarify this optimum range, an evaluation test is conducted using the LBP actual motor shown in FIGS. 3 and 4. In these figures, 7 represents the housing and 8 represents the hub (rotor) fixed on the axis 2. In addition, 9 denotes a thrust support in contact with the front end of the shaft to support the thrust load. The motor used in the evaluation test has a shaft diameter of 4 mm, a mirror, a rpm of 1000 and a temperature of 40 ° C.

5 shows the evaluation test results. In Fig. 5, the symbol? Indicates that there is no problem during the 1000 hours of continuous operation in the durability test. The symbol △ indicates that during 1000 hours of operation, the interval between 500 hours and 1000 hours is increased by the increase of the axial vibration (more than 5 μm), the increase of torque = the decrease of rpm (the rpm does not increase to 1000), and the emission of abnormal noise. The same problem is accompanied, indicating that normal operation becomes impossible. The symbol X indicates that the above problem has occurred for 500 hours after the start of operation.

From the results of the evaluation test, it can be seen that the optimum range (without X mark) for the opening factor and oil viscosity is a region enclosed by a straight line in FIG. 5, that is, a region satisfying the following condition.

(1) The ratio of the area of the opening in the bearing surface including the dynamic pressure generating groove is 2% or more and 20% or less.

(2) The kinematic viscosity of the holding oil to be filled at 40 ° C is 2 cSt or more.

(3) The ratio of the opening area and the kinematic viscosity of the oil at 40 ° C satisfy the following relationship.

(3/5) A-1≤η≤ (40/6) A + (20/3)

A: percentage of opening area (%)

η: kinematic viscosity of the oil at 40 ° C (cSt)

The selection of the opening factor and the value of the kinematic viscosity of the oil present in such a range generates a sufficient dynamic pressure oil film to support the shaft fluidly and to moderate the circulation of the oil, so that a rotation with high accuracy and longer life can be obtained.

Moreover, it is preferable that the ratio of opening area is 2% or more and 15% or less.

In the ratio of the depth h of the dynamic pressure generating groove 5 to the bearing gap (radial gap C) (see FIG. 7), it is considered that there exists more than an optimum range in which a sufficient dynamic pressure effect cannot be obtained. To clarify this optimum range, an evaluation test is carried out by replacing the shaft 2 of the LBP actual motor shown in FIG. 3 with a longer one, as shown in FIG. 6, to enable measurement of the axial vibration. The rpm is 10,000, the LBP actual motor has a shaft diameter of 4 mm and no mirror. In addition, the number 10 represents a non-contact displacement meter.

Under the above conditions, the value of the axial vibration is expressed as coordinates for c / h (c: radial gap, h: depth of groove), and the result shown in FIG. 8 is obtained. 8, it can be seen that when c / h is in the range of 0.5-4.0, the axial vibration is 5 mu m or less, but when smaller than 0.5 or larger than 4.0, the axial vibration is 5 mu m or more. Therefore, in order to maintain high accuracy, it is preferable that c / h = 0.5-4.0.

Porous oil-containing bearings are generally used for self-lubrication and the gradual consumption or overflow of oil due to the dispersion or evaporation of oil is inevitable. In that case, the reduction in the oil film generation range causes a drop in accuracy such as axial vibration. In particular, in the case of a laser printer (LBP) motor or a magnetic disk drive (HDD) motor, which is mainly used in a vertical position and used at a high speed of 10,000 rpm or more, as shown in FIG. 12, oil leaks under the action of centrifugal force. It tends to be difficult to maintain lubrication performance such as oil film generation.

For LBP and HDD, oil film exudation is fatal for maintaining rotational accuracy. In particular, in the case of one bearing body, the high speed rotation causes the oil to circulate inside the bearing while sucking in ambient air. Air sometimes enters the bearing openings. To prevent air from entering, an effective measure is to locate the oil supply member (oil supply member) as soon as a few voids are formed inside the bearing body.

In the present invention, as such an oil supply member, the solid body lubricating composition 3 consists of a synthetic resin material as a base material and oil as a lubricating component by mixing lubricating oil or lubricating grease, as shown in FIG. Is placed in contact with 1). The solid resin lubricating composition continuously exudes component oils to its surface at temperatures of at least 20 ° C., even in a dynamic state. With such a configuration, even when oil in the bearing body 1 flows, new oil is supplied from the resin lubricating composition 3 placed in contact with the bearing body 1 to the inside of the bearing body 1 by capillary action, Sufficient dynamic pressure oil film can always be produced between the body and the rotating shaft 2.

More specifically stated, the same lubricating grease and the average molecular weight and the oil and lubricant base oils, or 5-99% by weight of the same held in the bearing body held in the bearing body five days ^{1 × 10 6 - 5 × 10} 6 of 95-1 The solid lubricating composition (3) is produced by mixing the ultra-high molecular weight polyolefin powder by weight, heating the mixture to melt above the gelling temperature of the ultra-high molecular weight polyolefin and below the gelling temperature of the lubricating grease if lubricating grease is used, The melt is cooled and solidified.

That is, the formation of the resin lubricating composition in a solid mixture of lubricating oil or lubricating grease and ultra-high molecular weight polyolefin powder is characterized by low cost, mass production, easy operation for specification and simple operation. In addition, the solid resin lubricating composition, although very little by little, at a temperature above the average temperature (about 20 ° C.), gradually flows out the composition oil, enabling continuous supply of oil to the bearings. Fig. 9 shows the results obtained by using the solid resin lubricating composition 3 of the present invention as a test standard, and the oil separation ratio and the time left to stop are examined. It can be seen that the composition oil separates very little continuously for 1000 hours at a temperature of 20 ° C. The amount of separation increases with increasing temperature.

10 shows a comparison between when the solid resin lubricating composition is in contact with a bearing and when no oil supply member is used. In the absence of an oil supply member (denoted by the symbol ■), about 30% of the initial oil reserve flows in the operating time of about 2000 hours, and even when the oil retained flows from the bearing body (indicated by the symbol ●), the oil The silver is fed to the bearings and the loss is reduced to about 5%.

When used under conditions that produce a lot of heat due to high temperature atmosphere, high speed rotation, or friction, there is a time when too much oil is exuded from the solid resin lubricating composition, thus about 1-50% by weight as an oil bleeding inhibitor for the resin lubricating composition. Preference is given to mixing one or more materials, solid waxes, low molecular weight polyethylene, polyamide resins in an amount of.

As shown in FIG. 1, a cylindrical oil leakage preventing member 11 whose internal diameter is equal to or slightly larger than the bearing body 1 (porous oil-containing bearing A) is disposed on at least one axial side of the bearing body 1. do. The inner circumferential surface of the oil leakage preventing member 11 may be formed as an airflow generating groove 12 directed to a bearing body which creates airflow in the gap between the shaft 2 and the member, while rotating relatively between the member and the shaft. . The airflow generating groove 12 may be a plurality of inclined grooves. In the example shown, two bearing bodies 1 are vertically spaced apart from the oil leakage preventing member 11 disposed outside the upper bearing body 1. However, such a leakage preventing member 11 can also be arranged inside the bearing body 1. In addition, the oil leakage preventing member 11 may be provided on one or more sides of the bottom of the bearing body 1.

With this configuration, as shown in FIG. 11, with the rotation of the shaft 2, airflow is generated in the gap 13 between the shaft and the oil leakage preventing member 12, and is directed toward the bearing body 1 ( As shown in the figure, downwardly), even if the retaining oil flows from the bearing, it cannot pass through the gap 13 between the shaft 2 and the oil leakage preventing member 11. Oil leakage is suppressed by this action. In addition, when the shaft is dynamic, the capillary force in the gap 13 retains the oil so that there is no possibility of oil leakage when the rotation stops.

In this case, the oil leakage preventing member 11 is a porous body, and it is preferable that the gap 14 is defined between the member and the adjacent bearing body 1. With this configuration, the oil leakage preventing member 11 made of the porous body can absorb the oil leaking. In addition, when the shaft stops, oil between the oil leakage preventing member 11 and the shaft 3 is absorbed and the portion exposed to the air is reduced, so that the oil evaporation and generation of dust can be reduced. The oil absorbed by the oil leakage preventing member 11 enters the gap 13 with rotation and enters the bearing body 1 through the gap 14 by the airflow generated by the action of the airflow generating groove 12. Will be sent.

As shown in FIG. 1, the end face 11a and the chamfer 11b of the oil leakage preventing member 1 facing the bearing body 1 are polished so that the ratio of the opening area becomes 5% or less. In the case of sealing to the extent of full sealing, preferably, evaporation of oil and generation of dust absorbed by the oil leakage preventing member 11 can also be reduced.

As shown in FIG. 1, the bearing body 1 is press-fitted into the cylindrical housing 7 with one end open and the other end closed, and the solid resin lubricating composition 3 is received in contact with the bearing body 1. The oil leakage preventing member 11 is placed on the outside of the bearing body 1 so as to be adjacent to the opening of the housing 7. In this case, the dynamic pressure action is generated by the bearing, and as described above, since oil is always supplied from the resin lubricating composition 3, the generation of a sufficient dynamic pressure oil film can always be maintained, and a high accuracy for a long time is achieved. You can rotate. In addition, since oil leakage from the bearing is compensated by the oil leakage preventing member 11, no oil overflow occurs.

The gap 15 is defined between the inner end face 1a of the bearing body 1 opposite the bottom face 7 of the housing 7, and an air flow passage 16 is installed to allow the gap 15 and the outside of the housing to be spaced apart. Communicate with each other at a place other than the bearing gap 4, and the airflow passage 16 acts as an air bleeder. This configuration makes it easier to insert the shaft 2 in the assembly operation. In addition, during rotation, the internal pressure increases by the generation of heat, pushing the shaft (rotor) to make an unstable rotation. Such a situation can also be prevented.

A rotating member, for example a rotor 8, is attached to the rotating shaft 2, and a cross section of the bearing body 1 facing the rotor is formed of a herringbone or spiral dynamic pressure generating groove so that the shaft 2 rotates. In the case of supporting the thrust load by utilizing the dynamic pressure generated by the dynamic pressure generating groove while the radial load and the thrust load are supported, the thrust support 9 may be unnecessary.

In this case, it is preferable that the area ratio of the opening in the cross section of the bearing main body 1 in which the dynamic pressure generating groove is provided is 2% or more and 20% or less.

As is apparent from the above description, according to the present invention, the following effects are obtained.

(1) Environmental pollution due to oil flow, dispersion and evaporation can be reduced by a large amount.

(2) Unstable vibrations such as vortex can be suppressed to achieve high accuracy rotation by minimizing axial vibration.

(3) At all times, generation of sufficient oil film can be maintained.

(4) The durability can be greatly improved.

(5) The solid oil supply member is easy to operate and has high productivity.

An embodiment of the present invention will be described.

1 shows an example of a dynamic pressure porous oil-containing bearing device according to the present invention. Two bearing bodies 1 having bearing surfaces 17 are forcibly inserted into the housing 7 with one end open and the other end closed, and a shaft 2 (rotating shaft) is inserted into the bearing body 1, Two porous oil containing bearings A are spaced apart in the axial direction.

A solid lubricating composition (3) consisting of a synthetic resin as the base material and oil as a lubricating component by mixing lubricating oil or lubricating grease is disposed on the bearing body (1) on the open side (upper side) adjacent to the top opening in the housing (7). It is arranged between two bearing bodies 1 having an oil leakage preventing member 11. The upper surface 11a and the upper chamfer 11b of the oil leakage preventing member 11 are sealed. In addition, a gap 15 is defined between the end face 1a of the bearing body 1 on the closing side (lower side) and the bottom face 7a of the housing 7, and an airflow passage 16 is formed so that these gaps are formed. Communicate between (15) and the outside. This air flow passage 16 is formed by providing an axial notch at each outer surface of the bearing body 1, the resin lubricating composition 3, and the oil leakage preventing member 11. The inner circumferential surface of the bearing body 1 and the oil leakage preventing member 11 are formed with a plurality of inclined grooves (dynamic pressure generating grooves 5 and airflow generating grooves 12). The oil leakage preventing member 11 is made of a porous body which does not hold lubricating oil or the like. The materials of the bearing body 1 and the oil leakage preventing member 11 are not limited, and a known porous body having air gaps is formed by sintering or bubbled powder metal, iron, cast iron, copper, synthetic resin or ceramic material. The bearing body 1 and the oil leakage preventing member 11 are preferably made of a sintered alloy whose main material is iron or copper.

As shown in FIG. 1, a herringbone type dynamic groove 5 is formed on the bearing surface 17 of the bearing body 1, so that a dynamic oil film is generated during relatively rotation between the bearing gap and the rotation shaft 2. It can effectively suppress unstable vibration such as vortex. Further, in the bearing surface 17 (and the bearing surface shown in Fig. 4), the groove region 5 (filled with black) is inclined in the direction opposite to each other toward the axially opposite side, and the annular ridge line 6: the white region. Between these inclined groove regions (5: in the same figure, the annular ridges lie axially at the center of the bearing face) are formed. The width c of the bearing clearance 4 is, when the radius of the shaft 2 is R,

It is preferable that c / R = 1 / 2000-1 / 400.

If the groove depth is indicated by h,

c / h = 0.5-0.4

Is preferably, more preferably

c / h = 0.5-0.3.

Moreover, it is preferable that the ratio of the opening area in the bearing surface of the bearing main body 1 is 2-20% with respect to surface area ratio. If it is less than 2%, the circulation of oil is hindered, and if it is 20% or more, a dynamic pressure effect cannot be generated, so that a sufficient oil film is not produced. The oil viscosity is selected according to the ratio of the opening area.

The oil supply member 3 disposed in contact with the bearing body 1 may be a porous body of metal or resin or a known material such as a felt containing fibrous material, for example oil. It is preferable to use a resin lubricating composition which is solid and which continuously exudes component oils to the surface at a temperature of 20 ° C. or higher. The resin lubricating composition can be produced in a very simple way. For example, a predetermined amount of lubricating grease or lubricating oil is uniformly mixed with a predetermined amount of ultra-high molecular weight polyolefin powder, the mixture is poured into a die of a predetermined shape, and the mixture is heated to above the gelation temperature of the ultra-high molecular weight polyolefin, and grease is used. It is obtained by melting at a point lower than the dropping point of lubricating grease and by solidifying the mixture by cooling at calm. The ultra-high molecular weight polyolefins used in the present invention are polyethylene, polypropylene, polybutene or copolymer powders thereof, or a mixture of these powders, and the molecular weight of each powder has an average molecular weight of 1 × 10 ⁶ -1 × measured by the viscosity method. Is selected to be 10 ⁶ . Polyolefins within the range of such average molecular weights are superior to low molecular weight polyolefins in rigidity and oil retention and rarely flow even when heated to high temperatures. The proportion of such ultra-high molecular weight polyolefins in the lubricating composition is 95-1% by weight. The amount also depends on oil separation, roughness and hardness required for the composition. The higher the amount of ultra high molecular weight polyolefin, the higher the hardness of the gel after dispersion at a given temperature.

In addition, the lubricating grease used in the present invention is not particularly limited, and may be a metal salt concentrated or non-metal salt concentrated lubricated grease, and examples of such lubricated grease include lithium metal salt diester type, lithium metal salt mineral oil type, sodium metal salt mineral oil type, aluminum Metal salt mineral oil type, lithium metal salt diester mineral oil type, nonmetal salt diester type, nonmetal salt mineral oil type, nonmetal salt polyol ester type and lithium metal polyol ester type. The lubricating oil is not particularly limited, but examples thereof include diester type, mineral oil type, diester mineral oil type and polyol ester type. Further, the lubricating grease or the base oil of the lubricating oil is preferably the same as that held in the bearing body 1 from the beginning, but may be slightly different as long as the lubricating properties are not deteriorated.

The melting point of the ultra-ultra-molecular weight polyolefin is not constant because it varies depending on the average molecular weight, and the average molecular weight is 2 × 10 ⁶ as measured by the viscosity method, and the melting point is 136 ° C. As a product having the same average molecular weight, Mitsui Petrochemical Industries, Ltd. Miphenol (registered trademark) XM-220 produced by the company.

Therefore, in the case of dispersing and retaining lubricating grease or lubricating oil in a matrix of ultra-high molecular weight polyolefin, the material after mixing is heated to a temperature above the gelling temperature of the ultra-high molecular weight polyolefin and, if lubricating grease is used, is lower than its dropping point. Temperature, for example, 150-200 ° C.

Such bearing devices are used in a variety of applications, including, for example, various motors, including laser printer polygon mirror motors and magnetic disk drive spindle motors, and axial fans, ventilation fans, electric fans and other electrical applications, motors for vehicle electrical components, and the like. Oil significantly improves durability without contaminating the environment. That is, even when the oil originally retained in the porous oil-containing bearing flows, it does not flow out due to the presence of the oil leakage preventing member 11. In addition, since oil is supplied from the solid resin lubricating composition 3 to the bearing, the oil film in the bearing gap is always maintained, and high accuracy is achieved by the dynamic pressure action of the dynamic pressure generating groove 5 formed in the bearing surface of the bearing body 1. The rotation of can always be maintained. In addition, friction due to oil bleeding is suppressed, which greatly increases the service life. Unlike the felt, such a solid resin lubricating composition does not contain a fibrous material, so there is no problem with fibrous dust entering the bearing gap. In addition, since the composition is solid unlike grease, there is no possibility of wrapping around the axis of rotation, and therefore does not cause vibration of rotation. It is also solid, so it is very easy to adjust and can be effectively embodied during assembly operations.

In addition, since the bearing is not configured to use ferrofluidic sealing for sealing, the oil leakage preventing member 11, the bearing main body 1, and the oil supply member (solid resin lubricating composition: 3) are housed (7). It is fixed at the position to be press-fitted in, and assembling efficiency becomes high and cost falls.

Claims (36)

A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; In a dynamic pressure type porous oil-containing bearing having a dynamic pressure generating groove, The bearing fluidly supports the sliding surface of the shaft by a dynamic oil film generated in the bearing gap, and circulates the holding oil between the inside of the bearing body and the bearing gap through the opening of the bearing surface including the dynamic pressure generating groove. Bearing with dynamic pressure type porous oil. The method of claim 1, wherein at least one of the two factors, the ratio of the opening area on the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil. Dynamic pressure bearing containing porous oil, characterized in that set in. The method of claim 2, The openings are uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. The hydrodynamic porous oil-containing oil according to claim 1, 2 or 3, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. bearing. A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; It has a dynamic pressure generating groove, fluidly supports the sliding surface of the shaft by the dynamic oil film generated in the bearing gap, and circulates the holding oil between the inside of the bearing body and the bearing gap through the opening of the bearing surface including the dynamic pressure generating groove. Dynamic pressure porous oil bearing, It consists of a synthetic resin material as a base material and an oil as a lubricating component by mixing lubricating oil or lubricating grease, and has a solid resin lubricating composition which continuously and continuously exudes the component oil to the surface at a temperature of 20 ° C. or higher even in a dynamic state. , The bearing and the solid resin lubricating composition are in contact with each other through a contact surface, and the component oil in the solid resin lubricating composition is continuously exuded to the contact surface and fed into the interior of the bearing body. Bearing device. 6. The method of claim 5, wherein at least one of the two factors, the ratio of the opening area in the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil. Dynamic pressure porous oil-containing bearing device, characterized in that set in. The method of claim 5, The opening is uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing apparatus characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. The bearing device according to claim 5, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. 6. The solid lubricating composition according to claim 5, wherein the solid lubricating composition has the same lubricating grease and an average molecular weight of 1 × 10 ⁶ -5 as the oil retained in the bearing body, or the same 5-99% by weight of lubricant or base oil as retained in the bearing body. The ultra-molecular weight polyolefin powder having a size of 10 ⁶ is mixed, and the mixture is heated to melt above the gelation temperature of the ultra-high molecular weight polyolefin and below the gel point of the lubricating grease if lubricating grease is used, and is produced by cooling the solid to solidify it. Dynamic pressure bearing device containing porous oil. 10. The solid lubricating composition according to claim 9, wherein the solid lubricating composition is mixed with one or more materials as an oil efflux inhibitor selected from the group consisting of solid wax, low molecular weight polyethylene and polyamide resin in an amount of 1-50% by weight. Bearing type porous oil-containing bearing device. A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; It has a dynamic pressure generating groove, fluidly supports the sliding surface of the shaft by the dynamic oil film generated in the bearing gap, and circulates the holding oil between the inside of the bearing body and the bearing gap through the opening of the bearing surface including the dynamic pressure generating groove. A hydrodynamic porous oil bearing, and Disposed on one or more axial sides of the bearing, the inner diameter being equal to or slightly larger than the bearing body, creating an air flow towards the bearing body with a gap between the shaft while the inner surface rotates relatively between the shaft and the shaft; And a cylindrical oil leakage preventing member formed into an airflow generating groove. 12. The method of claim 11, wherein at least one of the two factors, the ratio of the opening area in the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil. Dynamic pressure porous oil-containing bearing device, characterized in that set in. The method of claim 11, The opening is uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing apparatus characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. 12. The bearing apparatus according to claim 11, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; It has a dynamic pressure generating groove, fluidly supports the sliding surface of the shaft by the dynamic oil film generated in the bearing gap, and circulates the holding oil between the inside of the bearing body and the bearing gap through the opening of the bearing surface including the dynamic pressure generating groove. A hydrodynamic porous oil bearing, and A solid resin lubricating composition composed of a synthetic resin material as a base material and an oil as a lubricating component by mixing lubricating oil or lubricating grease, and gradually exuding the component oil gradually to the surface at a temperature of 20 ° C. or more, Bearings, solid resin lubricating compositions, which are in contact with each other via a contact surface, wherein component oils in the solid resin lubricating composition are gradually exuded to the contact surfaces and fed into the interior of the bearing body; Disposed on one or more axial sides of the bearing, the inner diameter being equal to or slightly larger than the bearing body, creating an air flow toward the bearing body in a gap between the shaft while the inner surface is relatively rotated with the shaft; A dynamic pressure-type porous oil-containing bearing device, characterized in that it comprises a cylindrical oil leakage preventing member is formed into the air flow generating groove. 16. The method according to claim 15, wherein at least one of the two factors, the ratio of the opening area in the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil. Dynamic pressure porous oil-containing bearing device, characterized in that set in. The method of claim 15, The opening is uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing apparatus characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. 16. The bearing apparatus according to claim 15, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. 16. The solid lubricating composition according to claim 15, wherein the solid lubricating composition has the same lubricating grease and an average molecular weight of 1 × 10 ⁶ -5 as the oil retained in the bearing body, or the same lubricating grease as the oil retained in the bearing body. The ultra-molecular weight polyolefin powder having a size of 10 ⁶ is mixed, and the mixture is heated to melt above the gelation temperature of the ultra-high molecular weight polyolefin and below the gel point of the lubricating grease if lubricating grease is used, and is produced by cooling the solid to solidify it. Dynamic pressure bearing device containing porous oil. 16. The solid lubricating composition according to claim 15, wherein the solid lubricating composition is mixed with one or more materials as an oil efflux inhibitor selected from the group consisting of solid wax, low molecular weight polyethylene and polyamide resin in an amount of 1-50% by weight. Bearing type porous oil-containing bearing device. 12. The bearing device according to claim 11, wherein the oil leakage preventing member is made of a porous material, and a gap is defined between the bearing body and the bearing body. 22. The bearing apparatus according to claim 21, wherein the cross section and the chamfer of the oil leakage preventing member facing the bearing body are polished to be sealed so that the ratio of the cross section and the opening area of the chamfer is 5% or less. 16. The bearing body of claim 15, wherein the bearing body is secured to a cylindrical housing with one end open and the other end closed, the solid lubricating composition contained in the housing and contacting the bearing body, and the oil leakage preventing member of the bearing body adjacent the housing opening. A dynamic pressure porous oil-containing bearing device, characterized in that it is disposed outside. 24. A hydrostatic type as claimed in claim 23, wherein a space is defined between the inner end face of the bearing body opposite the bottom of the housing and an air flow passage is provided so that the gap and the outside of the housing communicate with each other at a location other than the bearing gap. Porous oil-containing bearing device. A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; It has a dynamic pressure generating groove, fluidly supports the sliding surface of the shaft by a dynamic oil film generated in the bearing gap, and circulates the holding oil through the opening of the bearing surface including the dynamic pressure generating groove between the inside of the bearing body and the bearing gap. A hydrodynamic porous oil bearing, and Having a rotating member attached to the shaft, Dynamic pressure-bearing bearing device characterized in that the thrust load of the shaft installed in the dynamic pressure generating groove on the end face of the bearing body opposite to the rotating member is supported by the dynamic pressure generated by the dynamic pressure generating groove in the cross section while the shaft rotates. . 26. The method of claim 25, wherein at least one of the two factors, the ratio of the opening area in the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil Dynamic pressure porous oil-containing bearing device, characterized in that set in. The method of claim 25, The opening is uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing apparatus characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. 27. The bearing apparatus according to claim 25, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. A bearing body made of a porous material, the bearing surface opposing the sliding surface of the shaft to be supported through the bearing gap, the oil retained in the bearing body by the inclusion of lubricating oil or lubricating grease, and the slope of the bearing surface of the bearing body; It has a dynamic pressure generating groove, fluidly supports the sliding surface of the shaft by the dynamic oil film generated in the bearing gap, and circulates the holding oil between the inside of the bearing body and the bearing gap through the opening of the bearing surface including the dynamic pressure generating groove. Dynamic pressure porous oil bearing, A solid resin lubricating composition composed of a synthetic resin material as a base material and an oil as a lubricating component by mixing lubricating oil or lubricating grease, and gradually exuding the component oil gradually to the surface at a temperature of 20 ° C. or more, Bearings, solid resin lubricating compositions, which are in contact with each other via a contact surface, wherein component oils in the solid resin lubricating composition are gradually exuded to the contact surfaces and fed into the interior of the bearing body; Having a rotating member attached to the shaft, Dynamic pressure-bearing bearing device characterized in that the thrust load of the shaft installed in the dynamic pressure generating groove on the end face of the bearing body opposite to the rotating member is supported by the dynamic pressure generated by the dynamic pressure generating groove in the cross section while the shaft rotates. . 30. The method of claim 29, wherein at least one of the two factors, the ratio of the opening area in the bearing surface including the dynamic pressure generating groove and the kinematic viscosity of the holding oil, is within a range capable of ensuring the generation of the dynamic oil film and the circulation of the holding oil Dynamic pressure porous oil-containing bearing device, characterized in that set in. The method of claim 29, The opening is uniformly distributed on the bearing surface including the dynamic pressure generating groove, The ratio of the opening area is 2% or more and 20% or less, The kinematic viscosity of the oil held at 40 ° C is 2cSt or more, The ratio and kinematic viscosity of the area are (3/5) A-1≤η≤ (40/6) A + (20/3) A: ratio of opening area (%) (eta): The dynamic pressure type porous oil containing bearing apparatus characterized by satisfy | filling the kinematic viscosity (cSt) of oil holding at 40 degreeC. 30. The bearing apparatus according to claim 29, wherein the ratio of the groove depth h of the dynamic pressure generating groove to the bearing clearance c is within a range of c / h = 0.5-0.4. The bearing apparatus according to claim 25, wherein the ratio of the opening area in the cross section of the bearing main body in which the dynamic pressure generating groove is formed is 2% or more and 20% or less. The hydrodynamic porous oil-containing bearing device according to claim 15, wherein the oil leakage preventing member is made of a porous material and a gap is defined between the bearing body and the bearing body. 35. The hydrodynamic porous oil-containing bearing device according to claim 34, wherein the cross section and the chamfer of the oil leakage preventing member facing the bearing body are polished to be sealed so that the ratio of the cross section and the opening area of the chamfer is 5% or less. The dynamic pressure type porous oil-containing bearing device according to claim 29, wherein the ratio of the opening area in the cross section of the bearing body in which the dynamic pressure generating groove is formed is 2% or more and 20% or less.